6. Spatial risk analysis

This section presents spatial analysis methods based on the statistical analysis of variables obtained by a spatial calculation, such as the aggregation of events into geographical units, or the belonging of an event to a space. These indirect methods do not directly involve the spatial relationships between individuals, they only involve belonging to the same space, and this is what differentiates them from the spatial analysis methods we presented in the previous sections. Nevertheless, they are widely used, not least because they enable risk analysis: if data on the susceptible population is available, aggregation can be used to calculate rates and proportions, to assess probabilities and risks, and to use other data characterizing the geographic units of aggregation.

The spatial calculations used fall into two groups: spatial aggregations, which create new variables...